It only takes one glance at the tabloid rack to realize that when famous people talk, people listen.

Celebrities often use their platform to discuss personal health and well-being.

Much of their health advice is considered questionable, from putting a jade egg in a private area to espousing the belief that vaccines cause autism .

Nonetheless, these comments tend to gain traction.

To be sure, not all celebrity health advice is bad, but experts say the comments of the rich and famous should be taken with a grain of salt.

Theyre not doctors

A celebritys fame can provide a big platform.

Because celebrities have a big audience, they can have a big effect on peoples behavior, Steven Salzberg, Ph.D., Bloomberg Distinguished Professor of biomedical engineering, computer science, and biostatistics at Johns Hopkins University, told Healthline. And if they give out bad advice, that can be very dangerous.

To find bad celebrity health advice, one doesnt have to look far.

Jenny McCarthy is as well-known for her anti-vaccine activism as she is for her Playboy pictorials.

Ben Stiller gave well-meaning but what some experts called flawed advice regarding prostate cancer screenings .

When it comes to Gwyneth Paltrow, its hard to know where to start.

In the past, the Oscar-winning actress has posted tips on her website about health-related topics from sunscreen to cleanses.

Most recently, Paltrow recommended that women put jade eggs in their vaginas to improve their health and sex life. That advice was criticized by a number of medical professionals.

Add to all this the dozens of celebs, including Kim and Kourtney Kardashian , who offer weight-loss tips.

Dr. Georges Benjamin, executive director of the American Public Health Association, says its risky for the general public to put their trust in celebrities.

Celebrities are seen through the lens of their fans as trusted messengers, Benjamin told Healthline. The challenge we have is making sure that those messages are correct and that those celebrities are well-informed. Frankly, sometimes, theyre simply wrong.

When it comes to the anti-vaccine movement, Salzberg says that anti-vaxxers like McCarthy tend to see a conspiracy.

Vaccines are one of the most effective treatments we have to prevent disease and save peoples lives, and thats why people go into medicine. They dont go into it because they want to hurt people. Thats just a crazy and nutty kind of suggestion, but thats exactly what Jenny McCarthy and other anti-vaxxers like Robert F. Kennedy Jr. are promoting now, Salzberg told Healthline. So theres no evidence that theres any conspiracy, but they state it and assert it, and people listen because they have a big platform. Its frustrating. Im not going to have the kind of audience that R.F.K., Jr. has. He had a meeting with Donald Trump .

Benjamin points out that sometimes it isnt an individual celebrity, but rather an entire industry, that spreads a harmful message.

The tobacco industry, for many, many years, encouraged and even paid studios and others in the entertainment industry to promote tobacco, which is, of course, a harmful product, he said. So the medical community has worked very hard with the TV and film industry to try and get them to remove the use of tobacco products from movies, where role models are seen smoking.

Good advice, education

Despite some of the more dubious health claims celebrities have made over the years, there are precedents for famous people using their platforms to advocate for responsible health decisions.

Benjamin cites actor Michael J. Foxs battle with Parkinsons disease, and his subsequent advocacy for research into the disorder, as a particularly noteworthy example.

He also brings up some other examples, noting, Katie Couric, whose husband had colon cancer, had her own colonoscopy on TV. The Marlboro Man, Wayne McLaren, became an anti-tobacco advocate after being diagnosed with lung cancer. Angelina Jolie, whose genetic makeup included a strong possibility of breast cancer, had a preventive double mastectomy. A celebrity can have a positive impact.

Salzberg says education is the key.

I think that the only real solution is a long-term one, to educate people better starting in grade school. They need to pay attention to science and evidence-based medicine, says Salzberg. The other thing that Ive been blogging about for years and other people, too is that I think we need to train individuals, starting as early as elementary school, to be skeptical about claims they hear on TV or on their computer screen. They dont have to become experts on science and medicine they just cant, it requires too much background training. But they can be skeptical.

Benjamin says that individuals can make informed choices by making sure their health advice is coming from a reputable source.

In this era, what often happens is a celebrity will bring something up, and people will begin googling it. It can begin a national conversation. Now, some of that conversation is informed and some of that information isnt informed, he said. And so what has to happen is that health organizations need to weigh in and become part of that conversation so people can find trusted information from organizations like the Red Cross, American Heart Association, American Cancer Society, and Id like to say us at the American Public Health Association. There are also federal agencies like the Centers for Disease Control and Prevention.

Salzberg points out that the scientific community has made significant headway in educating the public, particularly when it comes to anti-vaccine rhetoric.

I think the momentum has flagged, he said. The current anti-vaccine movement was at its peak in the early and mid-2000s, but in the scientific community weve been working very hard to counter that, because its very harmful to public health. So I think its losing momentum. But its a constant fight.

By Dan Gray

This story was originally published on Healthline.com.